Rapid-release escapement for timing programmers

ABSTRACT

Reduction gearing driven by a motor drives a toothed transmission wheel. A toothed advancement wheel is driven by the toothed transmission wheel and is provided with an axial pin having a short longitudinal nib, and a long longitudinal nib located diametrically opposite to the short nib. An output wheel has two partial rings of teeth one of which is in driven alignment with the short nib and both of which are in driven alignment with the long nib. A dwell wheel is coaxial with and has a lost motion connection with the output wheel, and has a partial ring of teeth in driven alignment with the long nib.

United States Patent Gazzani [151 3,672,234 51 June 27, 1972 [54]RAPID-RELEASE ESCAPEMENT FOR TIMING PROGRAMMERS [72] lnventor:

[73] Assignee:

Renato Gazzani, Frosinone, ltaly 0.M.P. Officine Meccanoplastiche DiPrecislone S.R.L., Frosinone, Italy [22] Filed: Sept. 30, i970 [21]Appl.No.: 76,894

[56] References Cited UNITED STATES PATENTS 2,871,702 2/1959 Tetro..74/112 X 3,319,477 5/1967 McVicker ..74/1 12 Primary ExaminerMiltonKaufman Attorney-Marshall & Yeasting ABSTRACT Reduction gearing drivenby a motor drives a toothed trans- [30] Foreign Application PriorityData 4 mission wheel. A toothed advancement wheel is driven by thetoothed transmission wheel and is provided with an axial pin Oct. 4,1969 Italy ..40523 A/69 having a short longitudinal nib, and a glongitudinal nib located diametrically opposite to the short nib. Anoutput [52] }J.S.(l ..74/3.5(2;,0 wheel has two partial rings of teamone of which is in driven [51] 3 H alignment with the short nib and bothof which are in driven [58] Field Search 7 alignment with the long nib.A dwell wheel is coaxial with and 200/38 38 38 33 3 A has a lost motionconnection with the output wheel, and has a partial ring of teeth indriven alignment with the long nib.

' 6 Claims, 4 Drawing Figures 22 L I I 1 1 7 R a I I6 the cycle and thenpermits it to RAPID-RELEASE ESCAPEMENT FOR TIMING PROGRAMMERS BACKGROUNDOF THE INVENTION This invention relates to an escapement for automatictiming programmers and, more particularly, to a rapid-release type ofescapement in which the time interval between the pulses, that is to saybetween the step-by-step forward movements of the escapement itself, isnot identical for every pulse. In particular, the interval of timerelating to a given group of pulses can be any integral multiple of thetime interval relating to another group of pulses. Furthermore, it isnot necessary for the pulses belonging to oneor the other group tofollow any specific order because. the order in which the pulses followeach other can be preset in any desired manner during the design stage.

In programmers equipped with an escapement according to the presentinvention it becomes possible to avoid double releases, a drawback thatis common to all hitherto known rapid-release programmers, by means of amechanical arrangementthat is not only certain in its action but alsocheap.

The escapement according to the present invention also supplies the saidprogrammer with an advancement system equipped with an extremely simplearrangement that automatically stops the advancement at any preselectedpoint of v 7 continue after a fixed and preselected interval of time. I

1. Field of the Invention The escapement in question can findapplication also in equipment other than timingprogramme'rs but, by wayof example that is not in any way to be considered limitative, it willhere be described as applied to a programmer for automatic electricdomestic appliances, such as washing machines, dish washers, andsimilar. In particular, the mechanism for the automatic stopping andrestarting of the forward motion can find practical application in themost recent techniques of designing and constructing washing machines.

2. DESCRIPTION OF THE PRIOR ART The hitherto known automatic programmershave been equipped with escapements that produce a step-by-stepadvancement of the group of cams activating the electric circuits, theseescapements being of two types:

a; Slow-release escapements. In these escapememse-during the phase ofadvancement-a lever or other mechanical means is guided by 'the sameeccentric that supplies the forward motion or byother mechanical means.This arrangement prevents an accidental advancement of more than onestep at a time and the consequent failure to respect the preselectedprogram. As against this, systems of this kind require the drive meansto be continually supplied with current throughout the phase ofadvancement, because the advancement is obtained by means of theaddition of a costly supplementary circuit, in actual practice known astransit contact, or by means of artificial phase differences in theprofiles of the eccentrics which reduce the machining tolerances andconsequently entail a considerable increase of the cost.

b. Rapid-release escapements. In this type of escapement theabove-mentioned drawbacks are eliminated thanks to the fact that thelever or other mechanical means of advancement is not braked during theadvancement phase and can therefore descend freely. In this way,however, it becomes possible, particularly during the phases of theprogram when the eccentrics absorb a comparatively small mechanicaltorque, for example by virtue of the lack of variations in the profilesof the eccentrics themselves, for so-called oversteps to occur, that isto say the advancement will not consist of just a single step as desiredand programmed, but rather of two or more steps; consequently there willbe irregular operation and the preselected program will not berespected. Generally speaking, attempts have been made to solve thisproblem by devising braking systems that intervene whenever necessary,for example energy flywheels, feedback springs, etc., but these systems,quite apart from being costly, do not provide a certain and absoluteguarantee against the possibility of an overstep.

Another drawback associated with programmers equipped with escapementsconstructed in accordance with hitherto known techniques is to be foundin the fact that the designers of the machines, in designing the cycles,are rigidly bound to a series of pulses whose time intervals areconstant and equal to each other, this being due to the fact thatprevious techniques were capable of offering differential pulses only bymeans of costly expedients; for example, the programmer could beequipped with two escapements or, as is the case with rapidreleaseprogrammers, the programmer could be fitted with specific control cams,one for each program, to ensure an appropriate choice of the pulseduration.

One of the objects of the present invention is therefore to provide anescapement of the rapid-release type for timing programmers in which thepossibility of an overstep occurring in the programmer is excluded in asure and mechanically certain manner. This object is achieved withoutrecourse to any supplementary mechanical means, but solely by means ofan appropriate arrangement of the mechanical elements needed for thestep-by-step advancement.

An advantageous characteristic of the present invention is to be foundin the limited number of mechanical means that are required by theadvancement system, in the low'cost of the said system, and in the factthat the system is operationally reliable for a long time owing to thecomplete absence of any parts whose action involves sliding friction.

Another object of the present invention is to provide an arrangementthat will permit the step-by-step advancement to be stopped at anydesired point of the cycle, the said stoppage being obtained in asimple, economic and mechanically certain manner, without the additionof any electrical control members and without the addition of anymechanical members that permit manual setting as in all hitherto knowncases.

Another object of the present invention is to provide an escapement forautomatic programmers in which the time interval between the pulses canbe varied from one'pulse to another, the intervals themselves beingcapable of being preselected without any limitation or restraint otherthan the fact that each of the said time intervals must be an integralmultiple of the duration that has been chosen for the basic pulse.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE INVENTIONBy referring to the drawings, it can be seen that the motor 11 ismounted outside the box that houses the movable pans of the mechanism;the output shaft of this motor is indicated byl 1a in FIG. 2.

, The motor 11 transmits its continuous rotatory motion through areducing mechanism consisting of the three toothed wheels l2, l3 and 14to a toothed transmission wheel 15 which can be clearly seen in FIG. 1and which rotates about the shaft A.

The toothed transmission wheel 15 is then coupled with one or more camwheels R for the operation of electric circuits the switching'of whichis required not in an intermittent manner, but rather in a continuousone. The addition of such cam wheels is optional and does not form partof the present invention.

The shaft A on which the toothed transmission wheel 15 is mounted alsocarries .a second toothed wheel 16, this latter 26, all of which will befurther I The second toothed wheel 16, rigidly fixed to the said firsttoothed wheel 15, has gear teeth only on a part of its circumference andtransmits its motion to the toothed wheel 17 which, as will be describedlater, drives both the lower and the upper ring of teeth of the wheelwhich is provided with a double ring of teeth.

The toothed part of wheel 16 is capable of driving wheel'l7 through anarc of slightly more than 90. The toothed wheel 17, as can be seen inthe view from below in FIG. 3 has on its lower side a double cam 18,that is to say a cam with two inversely symmetrical lobes.

As can be seen, each of the two lobes has one steep side and a moregently rising side. A wound spring 19 is mounted on a pin 20 fixed tothe base of the housing of the escapement. One arm of the spring is heldin position by the pin 21, this too being fixed to the base of thehousing of the escapement, and the other arm presses against the profileof the double cam 18 of the toothed advancement wheel 17.

In this way the rest positions of the wheel 17 are the ones in which thearm of the spring 19 rests on the two lowest parts of the profile of thedouble cam 18 and, every time the toothed part of wheel 16 drives thewheel 17, the arm of the spring 19 will run along the profile of thedouble cam until it passes one of the two high points. The force of thespring will then bring the wheel back into the rest position displacedby 180 from the former rest position, and so on. In this way a rotationof the wheel 17 through 180 is obtained for every complete revolution ofthe wheel 16 whose circumference is partly toothed.

The toothed wheel 17 is provided with an axial pin 22 which carries twolongitudinal nibs or noses placed diametrically opposite each other;more precisely, there is a short nib 23 which can engage only with thelower ring of teeth of the wheel 10 as well as a long nib 24 which iscapable of becoming engaged with both the lower and the upper ring ofteeth of wheel 10.

The wheel 16 has teeth only on a part of its circumference and themovement will therefore take place in the following manner:

The wheel 17 remains still for the whole of the period of time in whichit is faced by the toothless part of the circumference of wheel 16.After a predetermined interval of time, however, the wheel 16 engageswheel 17 and begins to drive it. Wheel 17, in turn, will wind the woundspring 19 by means of the double cam; this winding will continue untilthe arm of the spring 19 passes beyond the upper dead point. At thispoint wheel 16 once again becomes disengaged from wheel 17, wheel 17becomes idle, and the arm of the spring 19 returns to its former restposition. During this return phase the nib 23 or 24 becomes engaged withone of the tooth spaces of the lower ring of teeth of the wheel 10 anddrives it through an angle equal to the pitch of this lower ring ofteeth.

The nib 23 or 24, when in its rest position, remains engaged between twoteeth of the lower ring of teeth of the wheel 10. This wheel 10,therefore is no longer free to rotate and will remain in this positionuntil wheel 16 next becomes engaged with wheel 17 and the cam 18 becomesagain displaced from its rest position.

Without any supplementary mechanical means, this arrangement thereforeensures in a mechanically certain manner that the wheel 10 with the tworings of teeth will not be able to move forward by more than one step ata time.

The pitch of the teeth in the lower ring of wheel 10 corresponds to theduration of the first group of pulses desired in this embodiment.

In view of the fact that the two nibs 23 and 24 can act alternately' atintervals of 180 in the rotation of the toothed wheel 17, it can now beseen that the wheel 10 can be moved forward through desired incrementsthat will be governed by the relative positions and the relationshipsbetween the teeth and the empty spaces of the upper and lower rings ofteeth of the wheel 10. By way of example it should be noted that if oneof the teeth on the lower ring of teeth is missing, the short nib 23will turn idly and the wheel with two rings of teeth will obviouslyremain still for an interval of time that corresponds to the pitch ofthe lower ring of teeth.

Moreover, during the manual advancement of the cam block (not shown) foractuating electrical contacts, similar to the cam block R, which isattracted to the wheel 10, an operation that is generally required inpractical applications of programmers for the purpose of starting thecycles and other maneuvers, the nib 23 or 24 will be forced out of itsrest position between two adjacent teeth of the wheel 10 but, every timethe wheel 10 is moved forward manually through one complete pitch, itwill return into the next rest position, being pushed there by the biasof the spring 19 on the double cam 18.

If this operation of manual advancement is carried out at a time whenthe nibs 23 and 24 are not engaged with the teeth of wheel 10, then thestoppage of this wheel will be obtained by means of a conventionalratchet (not shown).

The wheel 10, to which said cam block (not shown) for actuatingelectrical contacts is attached, is the output member of the presentdevice.

SUMMARlZlNG Since the nib 23 is shorter than the nib 24 and since, inthe particular case that is being used as an example, the wheel 10 isprovided with two rings of teeth of which we will suppose the upper oneto have a pitch equal to the advancement it is desired to give to thecam block, while the other, the lower one, has either a tooth, or agroup of teeth or several groups missing, we will have a situation inwhich the short nib 23 turns idly and without moving the wheel 10 in allpositions in which the lower ring of teeth lacks a tooth; however, afterthe wheel 17 has rotated through the long nib 24 becomes engaged withthe upper ring of teeth of the wheel 10 and will make it move forward byone tooth. After a further rotation through 180 of the wheel 17 theshort nib 23 can again become engaged with the lower ring of teeth ofthe wheel 10.

Naturally, if there is a group of n teeth missing from the lower ring ofteeth, n revolutions will be required before the lower nib 23 can againbecome engaged with this ring of teeth.

By varying the position and the number of the teeth in the upper ring ofteeth of wheel 10, the position and the number of those pulses of theprogrammer cycle whose duration is determined by the long nib 24 can bevaried.

We will now make reference to FIGS. 1 and 4 and describe the arrangementfor stopping the, advancement in case one desires the wheel 10 with tworings of teeth to remain still for a prolonged interval of time, forexample for such length of time as corresponds to the forward movementof the wheel by a certain number of teeth. It can be seen that the wheel10 with two rings of teeth is provided with a fixed pin 25 which becomesengaged in a slot that has the form of a circular arc and is cut in awheel 26 with a toothed sector 260 that corresponds exactly to the areoccupied by the slot, the profile of the teeth of this sector being thesame as that of the teeth in the upper ring of teeth of wheel 10.

The length of the slot in the form of a circular arc is such that theangle it s'ubtends at the center of the wheel corresponds to the numberof teeth that defines the length of time during which one desires thewheel with two rings of teeth to remain still.

In normal conditions the pin 25 lies against the forward inner edge ofthe arc-shaped slot, that is to say the inner edge on the left of FIG.4. The pin 25 will therefore drive the toothed wheel 26 and make itrotate.

in the position of the program in which one desires, in this particularcase, to obtainthe stoppage of the forward movement the wheel 10 willlack a tooth both in its lower ring of teeth and in its upper ring ofteeth.

The tooth of the upper ring of teeth will be missing precisely in theposition corresponding to the pin 25. When the pin 25 finds itself inthe position shown in FIG. 4, tooth 26b of the toothed sector 26a ofwheel 26 comes in the same position as the missing tooth in the upperring of teeth of the wheel 10. It is as well to specify that the part ofwheel 26 that serves for this purpose is the one that finds itselfbetween a and b. It should be noted that the angle of the slot is equalto the angle between the first tooth on the right and the missing toothof wheel 26 (see a-b in FIG. 4).

At each subsequent revolution of the toothed wheel 17, the wheel whichhas a tooth missing from both rings of teeth will remain still as themissing teeth permit the nibs 23 and 24 to pass during their rotationwithout engaging any teeth on the wheel 10 and, therefore, the pin 25will also remain still; the toothed wheel 26, on the other hand, willduring each rotation of the wheel 17 be engaged by the nib 24 and thuswill move forward by one tooth, as indicated by the arrow, and we willtherefore have a relative movement between the pin 25 and the slot ofthe toothed wheel 26. The step-by-step rotation of the toothed wheel 26will continue until the backward inner edge of the slot, that is to saythe inner edge shown on the right of FIG. 4, will come into contact withthe pin 25 and will drive the wheel 10 forward by one step. In this waythe longer nib 24 of the toothed wheel 17 will again be able to engage atooth of the upper ring of teeth of wheel 10. However, since all theteeth of the toothed sector 26a have already been displaced from a to b,the longer nib 24 cannot drive the toothed wheel 26 which, moreover, iskept still by the ratchet 27, this ratchet being made of elasticmaterial and pivoted to the housing of the escapement.

The toothed wheel 26 therefore remains still, but the wheel 10 with tworings of teeth continues to rotate by virtue of the action of thetoothed wheel 17. As a result of the rotation of the wheel 10 the pin 25will again become displaced inside the slot of the wheel 26 and willreturn to the position shown in FIG. 4, that is to say the normalposition; it will thus come into contact with the forward inner edge ofthe slot and will begin to drive the wheel 26 forward again.

As hereinbefore stated, the wheels 10 and 26 are idle, in that they arefree to rotate about the shaft A, and they are driven only by the actionof the nibs 23 and 24. The wheel 26 functions, in the mannerhereinbefore described, as part of the mechanism for controlling theintermittent rotation of the output member 10.

What I claim is:

l. A rapid-release escapement for imparting a variety of intermittentmovements via an output wheel, comprising a motor, reduction gearingdriven by the motor, a toothed transmission wheel which is driven by thereduction gearing, a toothed advancement wheel which is driven by thetoothed transmission wheel and is provided with an axial pin having ashort longitudinal nib, and a long longitudinal nib locateddiametrically opposite to the short nib, an output wheel having twopartial rings of teeth one of which is in driven alignment with theshort nib and both of which are in driven alignment with the long nib,and a dwell wheel which is coaxial with and has a lost motion connectionwith the output wheel, and which has a partial ring of teeth in drivenalignment with the long nib.

2. A rapid-release escapement according to claim 1 wherein the toothedtransmission wheel has only a partial ring of teeth, and wherein eachrotation of the toothed transmission wheel drives the toothedadvancement wheel through a half rotation.

3. A rapid-release escapement according to claim 2 wherein the toothedadvancement wheel is provided with a cam having two parallel flat sides,and wherein a spring having a fixed mounting comprises a resilient legwhich normally lies against a flat side of the cam, to urge the cam intoone of two rest positions.

4. A rapid-release escapement according to claim 3 wherein in each restposition of the cam, one of the two nibs of the advancement wheelextends into a space between the teeth of at least one ring of teeth onthe output wheel in order to prevent overstepping of the output wheel.

5. A rapid-release escapement according to claim 1 wherein the lostmotion connection between the dwell wheel and the output wheel comprisesa pm which is fixed to one of said wheels and which extends into anareuate slot in the other wheel, and wherein a partial ring of teeth onthe dwell wheel subtends an angle equal to the angle of the arcuateslot.

6. A rapid-release escapement according to claim 5 com prising a ratchetwhich has a fixed mounting and which resiliently engages teeth on thedwell wheel.

i I i

1. A rapid-release escapement for imparting a variety of intermittentmovements via an output wheel, comprising a motor, reduction geaRingdriven by the motor, a toothed transmission wheel which is driven by thereduction gearing, a toothed advancement wheel which is driven by thetoothed transmission wheel and is provided with an axial pin having ashort longitudinal nib, and a long longitudinal nib locateddiametrically opposite to the short nib, an output wheel having twopartial rings of teeth one of which is in driven alignment with theshort nib and both of which are in driven alignment with the long nib,and a dwell wheel which is coaxial with and has a lost motion connectionwith the output wheel, and which has a partial ring of teeth in drivenalignment with the long nib.
 2. A rapid-release escapement according toclaim 1 wherein the toothed transmission wheel has only a partial ringof teeth, and wherein each rotation of the toothed transmission wheeldrives the toothed advancement wheel through a half rotation.
 3. Arapid-release escapement according to claim 2 wherein the toothedadvancement wheel is provided with a cam having two parallel flat sides,and wherein a spring having a fixed mounting comprises a resilient legwhich normally lies against a flat side of the cam, to urge the cam intoone of two rest positions.
 4. A rapid-release escapement according toclaim 3 wherein in each rest position of the cam, one of the two nibs ofthe advancement wheel extends into a space between the teeth of at leastone ring of teeth on the output wheel in order to prevent oversteppingof the output wheel.
 5. A rapid-release escapement according to claim 1wherein the lost motion connection between the dwell wheel and theoutput wheel comprises a pin which is fixed to one of said wheels andwhich extends into an arcuate slot in the other wheel, and wherein apartial ring of teeth on the dwell wheel subtends an angle equal to theangle of the arcuate slot.
 6. A rapid-release escapement according toclaim 5 comprising a ratchet which has a fixed mounting and whichresiliently engages teeth on the dwell wheel.